Expand JList row height depending on content

Question

I have a simple problem which totally drives me crazy.

I have a JList, and would like its cells to expand depending on their content, which is text of variable lengt

Answer 1

Not sure if there is an elegant way. One way that I know works is as follows : In getListCellRendererComponent()

• Use JLabel for the renderer
• Convert the text in question to HTML and use some logic to insert <br> in to the text where desired.
• Then set the text as text for the JLabel component and return.

Answer 2

there are maybe easiest and nicest way, I think that JTable with one TableColumn (and without TableHeader)in all cases better as JList, here is your Render MacOX version

then output should be

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.text.*;
//http://tips4java.wordpress.com/2008/10/26/text-utilities/
public class AutoWrapTest {

    public JComponent makeUI() {
        String[] columnNames = {" Text Area Cell Renderer "};
        Object[][] data = {
            {"123456789012345678901234567890"},
            {"ffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdx"},
            {"----------------------------------------------0"},
            {">>>>>>>>>>>>>ffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffffffd"
                + "ffffdffffddxffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdd"
                + "ffffdffffdffffffffdx>>>>>>>>>>>>>>>>>>>>>>>>>|"},
            {">>>>>>>>>>>>ffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffd"
                + "ffffdffffdx>>>>>>>>>>>>>>>>>>>>>>>>>>|"},
            {"a|"},
            {">>>>>>>>bbbb>>>>>>>>>>>>>>>>>>>|"},
            {">>>>>>>>>>>>>>>>>>|"},
            {">>>>>>>>>>>>>ffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffffffd"
                + "ffffdffffddxffffdffffdffffdffffffffd123456789012345678901234567890ffffdffffd"
                + "ffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffddx>>>>>>>>>>>>>>>>>>>>"
                + ">>>>>|"},
            {">>>>>>>>>>>>>ffffdffffdffffdffffffffd123456789012345678901234567890ffffdffffd"
                + "ffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffddxffffdffffdffffdffffffffd123456"
                + "789012345678901234567890ffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdffffdd"
                + "ffffffffd123456789012345678901234567890ffffddx>>>>>>>>>>>>>>>>>>"
                + ">>>>>>>|"},};
        TableModel model = new DefaultTableModel(data, columnNames) {

            private static final long serialVersionUID = 1L;

            @Override
            public boolean isCellEditable(int row, int column) {
                return false;
            }
        };
        JTable table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            @Override
            public void doLayout() {
                TableColumn col = getColumnModel().getColumn(0);
                for (int row = 0; row < getRowCount(); row++) {
                    Component c = prepareRenderer(col.getCellRenderer(), row, 0);
                    if (c instanceof JTextArea) {
                        JTextArea a = (JTextArea) c;
                        int h = getPreferredHeight(a) + getIntercellSpacing().height;
                        if (getRowHeight(row) != h) {
                            setRowHeight(row, h);
                        }
                    }
                }
                super.doLayout();
            }

            private int getPreferredHeight(JTextComponent c) {
                Insets insets = c.getInsets();
                View view = c.getUI().getRootView(c).getView(0);
                int preferredHeight = (int) view.getPreferredSpan(View.Y_AXIS);
                return preferredHeight + insets.top + insets.bottom;
            }
        };
        table.setEnabled(false);
        table.setShowGrid(false);
        table.setTableHeader(null);
        table.getColumnModel().getColumn(0).setCellRenderer(new TextAreaCellRenderer());
        //table.setPreferredScrollableViewportSize(table.getPreferredSize());
        JScrollPane sp = new JScrollPane(table);
        sp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        sp.setPreferredSize(new Dimension(250, 533));
        JPanel p = new JPanel(new BorderLayout());
        p.add(sp);
        return p;
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                createAndShowGUI();
            }
        });
    }

    public static void createAndShowGUI() {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        f.getContentPane().add(new AutoWrapTest().makeUI());
        f.setLocation(100, 100);
        f.pack();
        f.setVisible(true);
    }
}

class TextAreaCellRenderer extends JTextArea implements TableCellRenderer {

    private static final long serialVersionUID = 1L;
    private final Color evenColor = new Color(230, 240, 255);

    public TextAreaCellRenderer() {
        super();
        setLineWrap(true);
        setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        if (isSelected) {
            setForeground(table.getSelectionForeground());
            setBackground(table.getSelectionBackground());
        } else {
            setForeground(table.getForeground());
            setBackground(table.getBackground());
            setBackground((row % 2 == 0) ? evenColor : getBackground());
        }
        setFont(table.getFont());
        setText((value == null) ? "" : value.toString());
        return this;
    }
}

Answer 3

Try using JList's setFixedCellHeight() method.